Depth of cut adjustment construction for a radial-arm saw

ABSTRACT

The device disclosed herein is a radial-arm saw including a base frame having a horizontal worktable thereon. A one-piece, column and radial arm is pivoted on the base frame for movement about a generally vertical axis with the arm extending over the worktable. A motor-driven circular saw is suspended from the radial arm by a carriage which allows the saw to move along the arm and cut a workpiece on the worktable. Novel means is provided whereby the elevation of the saw blade relative to the worktable may be varied to thereby change the depth of cut performed by the saw blade on the workpiece.

United States Patent Francis J. Rosenthal, Jr.

Fork, Md.

Apr. 21, 1969 Feb. 23, 1971 The Black and Decker Manufacturing CompanyTowson, Md.

lnventor Appl. No. Filed Patented Assignee DEPTH OF CUT ADJUSTMENTCONSTRUCTION 108,886 11/1870 Curell Primary Examiner-Donald R. SchranAn0rneys-Leonard Bloom and Joseph R. Slotnik ABSTRACT: The devicedisclosed herein is a radial-arm saw including a base frame having ahorizontal worktable thereon. A one-piece, column and radial arm ispivoted on the base frame for movement about a generally vertical axiswith the arm extending over the worktable. A motor-driven circular sawis suspended from the radial arm by a carriage which allows the saw tomove along the arm and cut a workpiece on the worktable. Novel means isprovided whereby the elevation of the saw blade relative to theworktable may be varied to thereby change the depth of cut performed bythe saw blade on the workpiece.

PATENTEurEaza'xsn SHEET 1 BF 2 INVENTOR FRANCIS J. ROSENTHAL,JR.

ATTORNEY I PATENTEU FEB23 I971 SHEET 2 BF 2 INVENTOR FRANCIS J.ROSENTHAL. JR.

BY X

ATTORNEY DEPTH OF CUT ADJUSTMENT CONSTRUCTION FOR A RADIAL-ARM SAWSUMMARY OF THE INVENTION The present invention is directed to a simpleand effective saw elevating mechanism for a radial-arm saw. Thismechanism is operable by means disposed for ready accessibility by theoperator and requires that a minimumof saw component parts undergoelevation. Furthermore, the elevating mechanism itself involves aminimum of parts and obviates the need for close manufacturingtolerances.

Main objects of the present invention, therefore, are to provide a novelelevating mechanism fora radial-arm saw which embodies simplicity ofdesign, is positive in operation, eliminates close tolerances, and whichoverall is effective in performance.

Further important objects of the present invention are to provide anovel elevating mechanism" of the above character which is operable bymeans readily accessible to the operator and, during use, involveselevation of a minimum of parts.

Additional important objects are to provide a novel mechanism of theabove character which is relatively inexpensive to manufacture, ruggedin construction, and reliable in use. l

Other objects and advantages of the present invention will become moreapparent from a consideration of the detailed description to followtaken in conjunction with the drawings annexed hereto.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevationalviewillustrating a radial-arm saw construction embodying the presentinvention;

FIG. 2 is an enlarged view illustrating the saw and elevating mechanismof FIG. 1 from the reverse side thereof;

FIG. 3 is an enlarged sectional view of FIG. 2 taken along the line 3-3thereof;

FIG. 4 is an enlarged sectional view of FIG. 2 taken along the line 4-4thereof;

FIG. 5 is a view similar to FIG. 3 but showing the parts exploded; andFIG. 6 is a view similar to FIG. 2 and showing the parts in anotherelevated position.

BROAD STATEMENT OF THE INVENTION Broadly described, the presentinvention relates to a radialarm saw comprising a base having ahorizontal worktable supported thereon, column and arm means extendingupwardly from said base and over said worktable, respectively, carriagemeans including a frame movable along said arm means, circular saw meanspivoted upon said frame for movement about a horizontal axis and movablewith said carriage means to cut a workpiece on said table, means forpivoting said saw means relative to said frame to adjust the elevationof said saw means relative to said carriage means whereby to adjust thedepth of cut performed by said saw means on saidwork piece, saidelevation adjusting means comprising a rack and pinion on said saw meansand frame, respectively, a shaft rotatable on said frame and rigid withsaid pinion, resilient means between said shaft and said frame, firsttorque means adapted to deform said resilient means a firstpredetermined amount to develop a first predetermined frictional forceon said shaft, and second torque means independent of said first torquemeans and adapted to deform said resilient means a second predeterminedamount whereby to prevent turning movement of said shaft.

In another aspect, the present invention relates to a radialarm of thetype having a swivel arm supported in cantilever fashion over andparallel to a horizontal worktable, saw means movable along said am, theimprovement in said radial-arm saw wherein said saw means comprises aframe having an electric motor and saw unit pivoted by pivot means onsaid frame about a generally horizontal axis, rack and pinion meansmounted on said motor and saw unit and said frame for adjusting thepivoted position of said motor and saw unit, said pivot means beingadjustable in a plane generally perpendicular to said horizontal axis,whereby to compensate for tolerance variations between said rack andpinion,and means releasably locking said motor and saw unit to saidframe in selected pivotally adjusted positions.

DETAILED DESCRIPTION Referring now specifically to the drawings, aradial-arm saw construction embodying the present invention is seen inFIG. 1 to include base frames 11 having a pair of cleats 13(only one ofwhich is shown) secured thereto by fasteners 15. A worktable has astationary portion 17 secured to the cleats 13 in a suitable fashion anda removable portion 19 held against a work fence 21 by a plurality ofclamps 23 (only one of which is shown).

A columnsupport or collar 25 has a radial flange 27 secured atop thebase frame 11 by fasteners 29. The collar 25 is generally cylindrical incross section and is split along a major portion of its length and has apair of confronting radial flanges 31 (only one of which is shown)formed at the split edges. A column 33 extends upwardly from the baseframe 11 and has its lower end supported in the collar 25. The column 33is adapted to be locked in place within-the split collar 25 or releasedfor pivoting or swivel action therein by drawing up on or releasing theflanges 31 which, in turn,'changes the internal dimension of the collar25 accordingly'To this end, a clamp lever 35 extends through the flanges31 and is threaded into a trapped nut 37 so that by turning the lever inone direction or the other, the column 33 is locked or released,respectively.

A radial arm 39, formed integral or otherwise rigid with the column 33,extends over the worktable in cantilever fashion. A carriage 41 issupported for movement along the arm 39 by linear ball bearings (notshown) which ride in grooves or bearing races 43 (only one of which isshown) formed in the arm 39. A circular saw assembly 45 is suspendedfrom the carriage 41 and includes a frame or yoke 47 which is adapted toswivel about a generally vertical axis relative to the carriage 41 toaccommodate crosscutting" and ripping." The yoke 47, in turn, supportsan electric motor positioned within a housing 49 and a circular blade51, the latter being adapted to cut a workpiece (not shown) positionedon the worktable.

Thus, during crossc'utting," the saw assembly 45 is drawn across theworktable by means of a handle 53 whereas during ripping," the sawassembly 45 is swiveled relative to the position shown and locked andthe workpiece (not shown) is moved past the blade 51 and along the fence21 A locking lever 55 on the carriage provides for locking the sawassembly 45 in the crosscutting and ripping positions and for releasingthis assembly for movement from one of these positions to the other.

Novel means is provided to adjust the elevation of the saw blade 51relative to the worktable whereby to vary the depth of cut performed bythe blade 51. As shown in FIGS. 2 and 6, the motor housing 49 has a sawguard 57 rigid therewith and which encompasses substantially the upperportion of the saw blade 51. A generally L-shaped main pivot bracket 59is secured to the yoke 47 by a rivet 61 and is attached to an adjustmentbracket 63 by a pair of bolts 65, 67 and nuts 69, 71 (see FIG. 4). Therigid saw guard 57 and motor housing 49 are pivotally secured at one endby a volt 73, a nut 75, and an intervening, cup-shaped washer 77 to theadjustment bracket 63 for movement about a horizontal axis so that thesaw assembly 45 can pivot vertically. The rivet 61 provides anotherpivot whereby the saw. guard 57 and motor housing 49 can be adjusted forbevel cutting. A knob 78 provides for selectively releasing and lockingthe guard 57 and housing 49 in adjusted, bevel cutting positionsrelative to the yoke 47.

As shown in FIGS. 2, 3, 5 and 6, the other end of the saw guard 57 isprovided with an elongated arcuate slot 79 which has an arcuate gearrack 81 suitably fixed therein. A shaft 83 extends through a handlemounting yoke 85 rigid with the frame 47 and through the arcuate slot 79and has a pinion 87 pressed thereon which meshes with the gear rack 81.A knob 89 is secured at one end of the shaft by a setscrew 91 and isspaced from the yoke 85 by flat washers 88, 90 and a belleville washer92. Thus, when the knob 89 is turned, cooperation between the pinion 87and rack 81 causes the saw assembly 45 to pivot up or down about thepivot bolt 73.

Means is provided to frictionally retain the saw assembly 45 in anyadjusted position and whereby the saw assembly may be quickly and easilylocked in this or any position. As shown in F168. 3 and 5, a prevailingtorque nut 93 is threaded on the shaft 83 adjacent the other end thereoffrom the knob 89 and bears against a plastic washer 96 seated againstthe saw guard 57. A wing nut 97 is threaded on the shaft 83 outside thenut 93 and engages a cup-shaped washer 95. The washer 95 encases theprevailing torque nut 93 and bears against the plastic washer 96.

In assembly, the prevailing torque nut 93 is tightened to partiallycompress the belleville washer 92. The axial load on the torque nut 93acts on the shaft 83 so that the saw assembly 43 is frictionallyretained in any vertically adjusted position. However, the elevation ofthe saw assembly 43 may be changed or adjusted by turning the knob 89.This, in turn, causes the shaft 83 to turn and through meshingengagement between the pinion 87 and rack 81, the saw assembly 45 israised or lowered about the pivot 73.

When the desired elevation is attained, the saw assembly 45 is locked inplace by tightening down on the wing nut 97. This presses the cup-shapedwasher 95 against the plastic washer 96 and transfers the load from thetorque nut 93 to the wing nut 97 whereby the belleville washer 92 isfully compressed and the shaft 83 is locked in place. It will beappreciated that both the knob 89 and the wing nut 97 are readilyaccessible by the operator for quick and easy adjustment of the sawassembly 43.

As described briefly above, the saw assembly elevating mechanism isconstructed to accommodate small tolerance variations and yet providefor smooth and efficient operation. To this end, the pivot bracket 59has enlarged openings 101 (only one of which is shown) through which thebolts 65, 67 extend so that the pivot axis of the saw assembly 43 can beshifted laterally (See FIG. 4). Thus, with the parts assembled and withthe bolts 65, 67 snug but not fully tightened, the knob 89 is turned sothat the pinion 87 moves from one end of the rack 81 to the other. Whena smooth operation is achieved, bolts 65, 67 are tightened. This allowsthe pinion 87 and rack 81 to achieve a smooth operation withoutrequiring a critical manufacturing tolerances that otherwise would benecessary.

By the foregoing, there has been provided a novel depth of cutadjustment construction for a radial-arm saw calculated to fulfill theinventive objects herein and while a preferred embodiment has been setout, various additions, substitutions, modifications and omissions maybe made thereto without departing from the spirit of the invention asencompassed by the appended claims.

lclaim:

l. A radial-arm saw comprising a base having a horizontal worktablesupported thereon, column and arm means extending upwardly from saidbase and over said worktable, respectively, carriage means including aframe movable along said arm means, circular saw means pivoted upon saidframe for movement about a horizontal axis and movable with saidcarriage means to cut a workpiece on said table, means for pivoting saidsaw means relative to said frame to adjust the elevation of saw meansrelative to said carriage means, whereby to adjust the depth of cutperformed by said saw means on said workpiece, said elevation adjustingmeans comprising a rack and pinion on said saw means and frame,respectively, a shaft rotatable on said frame and rigid with saidpinion, resilient means between said shaft and said frame, first torquemeans adapted to deform said resilient means a first predeterminedamount to develop a first predetermined frictional force on said shaft,and second torque means independent of said first torque means andadapted to deform said resilient means a second predetermined amount,whereby to prevent turning movement of said shaft.

2. A construction as defined in claim 1 wherein said pivot means isadjustable in a plane generally perpendicular to said horizontal axis.

3. A construction as defined in claim 2 wherein said pivotallyconnecting means comprises interconnecting first and second brackets onsaid frame and said saw means, respectively.

4. A construction as defined in claim 3, said second bracket is pivotedon said saw means and is adjustable relative to said first bracket in aplane generally perpendicular to said horizontal axis.

5. A construction as defined in claim 1 wherein said resilient meansincludes belleville washer means, said first torque means includes aprevailing torque nut on said shaft and operatively engageable with saidframe, said second torque means includes a manually manipulatable nut onsaid shaft and operatively engageable with said frame independently ofsaid first torque means.

6. A construction as defined in claim 1 wherein said rack is arcuate inconfiguration and is formed on a radius from said pivot means.

7. In a radial-arm saw of the type having a swivel arm supported incantilever fashion over and parallel to a horizontal worktable, sawmeans movable along said arm, the improvement in said radial arm sawwherein said saw means comprises a frame having an electric motor andsaw unit pivoted by pivot means on said frame about a generallyhorizontal axis, rack and pinion mounted on said motor and saw unit andsaid frame for adjusting the pivoted position of said motor and sawunit, said pivot means being adjustable in a plane generallyperpendicular to said horizontal axis, whereby to compensate fortolerance variations between said rack and pinion, and means releasablylocking said motor and saw unit to said frame in selected pivotallyadjusted positions.

8. A construction as defined in claim 7 wherein said pinion is fixed toa shaft rotatably supported upon said frame, and said releasable lockingmeans locks said shaft against turning.

9. A construction as defined in claim 8 which includes friction meansoperable independently of said locking means to retard turning movementof said shaft.

10. A construction as defined in claim 9 wherein said friction meansincludes belleville washer means on said shaft, and torque means actingon said shaft and adapted to deflect said belleville washer means.

11. A construction as defined in claim 10 wherein said releasablelocking means comprises another torque means acting on said shaftindependently of said first-mentioned torque means and adapted to locksaid shaft.

12. A construction as defined in claim 7 wherein said pivot meansincludes a pair of adjustably interconnected bracket members carried bysaid frame and said motor and saw unit, respectively.

13. A construction as defined in claim 12 wherein one of said bracketmembers is pivoted to said frame for movement about another horizontalaxis generally perpendicular to said first-mentioned axis, whereby saidmotor and saw unit can be adjusted for bevel cutting.

1. A radial-arm saw comprising a base having a horizontal worktablesupported thereon, column and arm means extending upwardly from saidbase and over said worktable, respectively, carriage means including aframe movable along said arm means, circular saw means pivoted upon saidframe for movement about a horizontal axis and movable with saidcarriage means to cut a workpiece on said table, means for pivoting saidsaw means relative to said frame to adjust the elevation of saw meansrelative to said carriage means, whereby to adjust the depth of cutperformed by said saw means on said workpiece, said elevation adjustingmeans comprising a rack and pinion on said saw means and frame,respectively, a shaft rotatable on said frame and rigid with saidpinion, resilient means between said shaft and said frame, first torquemeans adapted to deform said resilient means a first predeterminedamount to develop a first predetermined frictional force on said shaft,and second torque means independent of said first torque means andadapted to deform said resilient means a second predetermined amount,whereby to prevent turning movement of said shaft.
 2. A construction asdefined in claim 1 wherein said pivot means is adjustable in a planegenerally perpendicular to said horizontal axis.
 3. A construction asdefined in claim 2 wherein said pivotally connecting means comprisesinterconnecting first and second brackets on said frame and said sawmeans, respectively.
 4. A construction as defined in claim 3, saidsecond bracket is pivoted on said saw means and is adjustable relativeto said first bracket in a plane generally perpendicular to saidhorizontal axis.
 5. A construction as defined in claim 1 wherein saidresilient means includes belleville washer means, said first torquemeans includes a prevailing torque nut on said shaft and operativelyengageable with said frame, said second torque means includes a manuallymanipulatable nut on said shaft and operatively engageable with saidframe independently of said first torque means.
 6. A construction asdefined in claim 1 wherein said rack is arcuate in configuration and isformed on a radius from said pivot means.
 7. In a radial-arm saw of thetype having a swivel arm supported in cantilever fashion over andparallel to a horizontal worktable, saw means movable along said arm,the improvement in said radial arm saw wherein said saw means comprisesa frame having an electric motor and saw unit pivoted by pivot means onsaid frame about a generally horizontal axis, rack and pinion mounted onsaid motor and saw unit and said frame for adjusting the pivotedposition of said motor and saw unit, said pivot means being adjustablein a plane generally perpendicular to said horizontal axis, whereby tocompensate for tolerance variations between said rack and pinion, andmeans releasably locking said motor and saw unit to said frame inselected pivotally adjusted positions.
 8. A construction as defined inclaim 7 wherein said pinion is fixed to a shaft rotatably supported uponsaid frame, and said releasable locking means locks said shaft againstturning.
 9. A construction as defined in claim 8 which includes frictionmeans operable independently of said locking means to retard turningmovement of said shaft.
 10. A construction as defined in claim 9 whereinsaid friction means includes belleville washer means on said shaft, andtorque means acting on said shaft and adapted to deflect said bellevillewasher means.
 11. A construction as defined in claim 10 wherein saidreleasable locking means comprises another torque means acting on saidshaft independently of said first-mentioned torque means and adapted tolock said shaft.
 12. A construction as defined in claim 7 wherEin saidpivot means includes a pair of adjustably interconnected bracket memberscarried by said frame and said motor and saw unit, respectively.
 13. Aconstruction as defined in claim 12 wherein one of said bracket membersis pivoted to said frame for movement about another horizontal axisgenerally perpendicular to said first-mentioned axis, whereby said motorand saw unit can be adjusted for bevel cutting.